Spinal Cord And Hindbrain Flashcards
Where does the spinal cord proper extend to and from ?
From the foramen magnum to the 1st/2nd lumbar vertebrae
Which regions of the cross section of the spinal cord have a larger ventral horn ?
The cervical and lumbar regions have larger ventral horns. The thoracic region has a smaller ventral horn region because it controls the trunk so not many motor neurones are coming out. Thoracic region has a more prominent lateral horn where preganglionic neurones are present
What is lamina 1 called ?
Nucleus posteromarginalis
What is laminae 2 called ?
Substantia gelatinosa
What are laminae 3,4,5 called ?
N.proprius
Where is laminae 7 situated and what is it called ?
Situated in the intermediate horn. It’s called the interomediolateral nucleus. Contains inter neurones to connect different laminae
Where is laminae 9 and what is it called ?
Laminae is in the ventral horn and it’s a motor nucleus
What are the subdivisions of the vertebral column ?
Cervical = 8 Thoracic= 12 Lumbar=5 Sacral=5 Coccygeal
What is present in the grey matter ?
Neuronal cells bodies Dendrites Axons Afferent terminals Glia
What is present in the White matter ?
Axons of ascending and descending tracts
Which laminae are part of the dorsal horn and what are they called ?
Lamina 1- nucleus posteromarginalis
Lamina 2- substantia gelatinosa
Lamina 3,4 and 5 - N.propius
Which lamina is part of the intermediate horn ?
Lamina 7 - intermediolateral nucleus
Which lamina is part of the ventral horn ?
Lamina 9 -motor nucleus
What parts of the body do the motor neurones of the ventral horn control ?
Medial part controls the neck and trunk
Lateral part controls the digits
Organisation is important because descending pathways can be in close proximity but not interfere with each other
What are the spinal meninges ?
Protect the spinal cord
Dura mater = thickest outer layer which attaches to the skull
Arachnoid mater= this is in very close association with the dura mater
Pia mater- this is the layer closest to the spinal cord and it is very thin
Where are the cell bodies of sympathetic preganglionic neurones ?
Thoracic and lumbar levels =thoraco-lumbar
Where are the cell bodies of the parasympathetic preganglionic neurons ?
Sacral levels or BRAINSTEM
Where are the cell bodies are sympathetic post ganglionic neurons found ?
Sympathetic chain
Where are the cell bodies of parasympathetic post ganglionic neurons found ?
Close to the target tissue
What is the difference between somatic motor and autonomic outflow ?
The autonomic system has 2 branches (pre and post ganglionic neurons) whereas somatic system has only one neuron output
Explain the lengths of the pre and post ganglionic neurons in the sympathetic and parasympathetic systems ?
Sympathetic
Preganglionic neurons are short
Post ganglionic neurones are long so they can reach the target
Parasympathetic
Preganglionic neurons are long
Post ganglionic neurons are short because their cell bodies are close to their target
What are the 3 subdivisions of the White matter ?
Posterior funiculus
Lateral funiculus.
Anterior funiculus
These areas contain ascending, descending and propriospinal fibres to link different segments
What tracts are present in the posterior funiculus ?
Also known as dorsal column
Ascending tracts of gracile and cuneate fasiculi
The gracile receive inputs from lower part of the body
The cuneate receives inputs from the upper part of the body
These pathways are important for fine motor control - allow very rapid transmission
What tracts are present in the antero-lateral regions of the White matter ?
Contains ascending fibres of spino-thalamic pathway
-critical for pain and temperature control
Send tracts to the thalamus and cortex indicating where the painful stimulus is
What are the pathways important in controlling the trunk ?
The reticulospinal and vestibular spinal pathways
What pathways are important in controlling the distal musculature for fine movement ?
Corticospinal and rubrospinal pathways
What is syringomyelia ?
Expansion of the spinal canal
This affects the crossing fibres which normally causes bilateral loss of temperature and pain sensation
What is brown-sequard ?
Causes loss of pain and temperature from the contralateral side
Loss of touch, proprioception and vibration from ipsilateral side
What are the symptoms caused by spinal cord injuries which cause autonomic dysfunction ?
Severe postural hypotension - loss of consciousness
Incontinence
Impotence
What is motor neurons disease ?
It is the degeneration of upper and lower motor neurons
What are the symptoms of motor neurons disease ?
Muscle weakness
Loss of voluntary movements but eye, bladder and bowl movements maintained
However you maintain cognitive function
What does the hindbrain include ?
Medulla oblongata- myelencephalon
Pons- metencephalon
What is the BRAINSTEM ?
Hindbrain + midbrain
What is the trigeminal system ?
Consist of subnuclei pralis, interpolaris and caudalia
They process sensory inputs from the oro-facial regions
What is pyramidal decussation ?
It is part of the motor pathway in which motor fibres coming down from the cortex are crossing
What can be seen on the dorsal surface of the BRAINSTEM ?
- floor of 4th ventricle
- trigeminal system
- components of vestibular system
- pyramidal decussation
- inferior and superior colliculus
- cerebellar peduncle a
- gracile and cuneate tubercles
What can be viewed on the ventral surface of the BRAINSTEM ?
Medulla- not the reticular formation or gracile and cuneat but raphe and ventralateral medulla are seen
Pons
The associated cranial nerves of the medulla and pons are also seen = include 6-12
Other cranial nerves are also seen - 2, 3, 4, 5
What are the somatic motor nucleus’ in the BRAINSTEM ?
- abducens, hypoglossal, trochlear, oculomotor
What are the general sensory nuclei found in the BRAINSTEM ?
Principal trigeminal nucleus, spinal trigeminal
What special sensory nuclei are found in the BRAINSTEM ?
Vestibular and cochlear nuclei
What are the visceral motor nuclei found in the BRAINSTEM ?
Edinger-Westphal, saliva tort and dorsal motor nucleus of vagus
What visceral sensory nuclei are found in the BRAINSTEM ?
Nucleus of the solitary tract
What are the brachial motor nuclei found in the BRAINSTEM ?
Trigeminal motor nucleus, facial motor, accessory and nucleus ambiguus
What happens at the caudal medulla ?
90% of the descending corticospinal tracts decussate to cross the midline
What is wallenbergs syndrome ?
Caused by thrombosis of vertebral artery
Causes a wide range of sensory and motor deficits
- contralateral loss of pain/temp sensitivity due to the anterolateral system
- ipsilateral loss of pain/temp from the face due to trigeminal system
-vertigo/nystagmus due to the vestibular nerve
- ipsilateral loss of taste due to solitary tract
- dysphasia
What are BRAINSTEM gliomas ?
They are BRAINSTEM tumours and they account for 10-20% of childhood tumours
Symptoms: double vision, weakness, unsteady gait, difficulty swallowing, drowsiness, nausea and vomiting
By 3 years 13% are still alive
What are the functions of the reticular formation ?
The ascending system controls sleep, attention and awakefulness
The descending system of fibres form the reticulospinal tract contributing to posture and postural reflexes
Also contributes to heart rate and respiration
What are the 3 nuclei of the raphe nucleus ?
Pallidus
Obscurus- in medulla
Magnus-in pons
What arthe functions of the raphe nucleus ?
Medullary nuclei (obscurus) project to spinal cord to modulate pain, movements and autonomic control Most rostral nuclei project to higher brain regions to modulate pain, mood, sleep wake cycle The raphe Magnus is important in controlling descending pain stimuli
